摘要
大量风机控制和电力变换设备集中布置于风机塔筒底部,易遭受雷电反击过电压而损坏。建立了考虑风机钢筋混凝土基础自然接地作用的雷击瞬态模型,采用频域矩量法进行求解,通过傅里叶反变换获得设备安装位置的时域瞬态过电压波形和冲击阻抗。计算结果表明,考虑混凝土中的钢筋能显著降低风机雷电冲击接地电阻和塔筒底部电位抬升,在高土壤电阻地区影响更加明显;风机承台中的钢筋散流作用明显,考虑承台钢筋时风机冲击接地电阻和塔筒底部电位升明显减小,随着垂直桩基数量的增加,风机冲击接地电阻值和塔筒电位升进一步降低。垂直桩基分布在承台边缘附近较分布在承台中央附近散流效果更加良好,冲击接地电阻和塔筒底部电位抬升相对较小;雷击瞬态过电压波形呈现明显的衰减振荡,振荡频率约为0.5~0.6 MHz,随风机冲击接地电阻值增大振荡频率呈减小趋势。
A large number of wind turbine control and power conversion equipments are centrally located at the bottom of the wind turbine tower and are susceptible to damage from lightning backlash overvoltage. A lightning transient model considering the natural grounding action of the reinforced concrete foundation of a wind turbine is developed and solved using the frequency domain moment volume method to obtain the time-domain transient overvoltage waveform and impulse impedance at the equipment installation location by the inverse Fourier transform. Calculation results show that, considering the reinforcement in concrete can significantly reduce the grounding resistance of lightning impact and tower potential rise at the bottom, in areas of high soil resistance is more obvious;the diffusion effect of steel in wind turbine bearing is obvious, the impact grounding resistance and tower potential rise at the bottom decreased significantly when considering the bearing steel, and with the increase in the number of vertical pile foundations, the value of impact grounding resistance and tower potential rise to further reduce. Vertical pile foundations distributed near the edge of the bearing disperse flow more effectively than those distributed near the center of the bearing, impact grounding resistance and tower potential rise at the bottom is relatively small;lightning transient overvoltage waveform shows obvious attenuation oscillation, oscillation frequency of about 0.5~0.6 MHz, the oscillation frequency tends to decrease as the impact grounding resistance of the wind turbine increases.
作者
孙通
李伟
张博
夏晖
张石
向念文
许益纬
霍焕杰
朱博
SUN Tong;LI Wei;ZHANG Bo;XIA Hui;ZHANG Shi;XIANG Nianwen;XU Yiwei;HUO Huanjie;ZHU Bo(Long Yuan(Beijing)Wind Power Engineering Technology Company Limited,Beijing 100034,China;School of Electrial Engineering and Automation,Hefei University of Technology,Hefei 230009,China)
出处
《电瓷避雷器》
CAS
北大核心
2022年第1期29-35,共7页
Insulators and Surge Arresters
关键词
风机
雷击
塔筒电位升
矩量法
波过程
wind turbine
lightning
tower potential rise
moment of method
wave process
